1. Technical Field
The present invention relates to an input source search support method, and an image display apparatus and a projector using the search support method.
2. Related art
Generally, a plurality of input sources (e.g., image input devices such as PC, DVD and VTR, and the Internet) can be connected to a projector as an image display apparatus. FIG. 16 illustrates a related-art projector 500 to which a plurality of input sources are connected.
As illustrated in FIG. 16, the projector 500 produces image light corresponding to the desired input source of the plural input sources PC1, PC2, VTR, and DVD and projects the light on a screen S. Input/output interfaces used in the projector 500 in recent years are LAN (wireless or wire) interfaces, as well as input/output interfaces (Icomputer1, Icomputer2, Ivideo, Is-video) shown in FIG. 16.
When this type of projector is used, a desired input source for providing projection display needs to be selected from available input sources. It is, therefore, convenient if information such as what input source of the plural input sources is available and what display it is providing can be easily obtained.
FIG. 17 shows a related-art input source search support method.
When input source switching command is inputted through a mode switch or a remote controller in the related-art input source search support method shown in FIG. 17, the next input source of the currently selected input source is stored in a flag of a RAM (step S940) to display the name of the input source stored in the RAM by OSD (step S941). Subsequently, switching signals requiring image signals to be outputted from the switched input source are outputted to an input switching device (step S942). After time-up of the timer (step S943), the OSD display is deleted (step S944). The input source is switched to another input source, in such a manner as from Video 1 to Video 2, Option, and other devices, for example, every time the input source switching command is inputted (for example, see JP-A-2000-081666).
In the related-art input source search support method, therefore, the input source is switched sequentially in accordance with the input source switching command inputted from the user. In this case, information such as what input source is available and what display is currently provided can be securely checked.
In the related-art input source search support method, however, processes required for this method are complicated and inconvenient since it is necessary to sequentially switch the input sources while checking whether or not available are input sources including input sources currently unavailable (such input sources as not powered or not connected with the projector). The problem will be more serious if a number of input sources can be connected with the projector as in the cases in recent years. Accordingly, another improved type of related-art image search support method capable of solving these problems has been proposed.
FIG. 18 shows the other improved type related-art input source search support method.
The related-art input source search support method shown in FIG. 18 automatically searches for the next input source by detecting image signals while skipping input sources currently unavailable if any, during search for the input source. In this input source search support method, therefore, the input sources currently unavailable which may be contained in the search target input sources are skipped and the next input source is automatically searched. In this case, it is unnecessary to sequentially switch the input sources while checking whether the input sources are available or not and the like. As a result, processes required for this method can be facilitated and thus the usability can be enhanced (for example, see General catalog for business projector ((Epson Sales Japan Corporation, Seiko Epson Corporation) catalog code: CLELSG16A (2004.12.15)) (page 3 (description of Automatic Detection of Image Signals)).
In the related-art improved type input source search support method, however, nothing is displayed on the screen when all the input sources including the initially selected input source are unavailable and thus all the input sources are skipped. In this case, the user does not understand why nothing is displayed and is thus bewildered. This deteriorates the usability of the projector.
Additionally, in the related-art improved type input source search support method, input sources in the so-called stand-by condition (input source from which image signals have not been generated yet even though they are connected with the projector and powered, hereinafter referred to as stand-by input sources) are skipped similarly to the input sources unavailable. Thus, the user cannot select the stand-by input sources even if they are desired input sources.
These problems occur not only in the projector at the time of searching for input sources, but also in another image display apparatus to which a plurality of input sources can be connected at the time of searching for input sources.